Connect External Current Transducer Common on TB-4302C

Updated Sep 17, 2026

Reported In

Hardware

  • PXIe-4302
  • PXIe-4303
  • TB-4302

Issue Details

I am connecting an externally powered or three-wire 4–20 mA current device to an NI PXIe-4302 or PXIe-4303 using the TB-4302C terminal block. I am unsure whether the device common/return line should be connected to AISENSE or AIGND. I also want to know whether a specific AISENSE terminal must be used or if any AISENSE terminal on the terminal block is acceptable.

Solution

Connect the common/return lead of the externally powered 4–20 mA device to AISENSE, not AIGND.
  • Connect the current signal output lead to the desired analog input channel (for example, AI0).
  • Connect the device common/return lead to any AISENSE terminal on the TB-4302C.
  • Use the AISENSE terminal closest to the channel for wiring convenience if desired.
  • Install an external bias resistor between AISENSE and AIGND when using a floating or isolated external power supply, following the recommendations in the device documentation.
The TB-4302C internally connects all negative analog input connections to the AISENSE node through the current measurement circuitry. As a result, AISENSE provides the signal return path for current measurements.
AIGND is not intended to function as the signal return path for the current loop. Instead, AIGND serves as the module ground reference and may be used with an external bias resistor when required by the measurement configuration.

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